Rescue response … People carry a person who was struck by a car on Red River Street in downtown Austin, Texas, at SXSW music and film festival. Source: AP

A SUSPECTED drunk driver fleeing police crashed through barricades at the South By Southwest festival in Austin, Texas, slamming into a crowd outside a nightclub and killing a man on a bicycle and a woman on a moped early on Thursday.

Austin Police Chief Art Acevedo said at a news conference that the motorist drove down a crowded street and ran into people in front of a nightclub around 12:30am (4:30pm AEDT), injuring 23 people. He eventually crashed and tried to make a getaway on foot, but a police officer shocked him with a stun gun and took him into custody, Mr Acevedo said.

The victims were a woman from Austin and a man from the Netherlands, Mr Acevedo said. A man who was also on the moped is in good condition, he said. No names have been released.

The driver, whose name also has not been released, faces two counts of capital murder and 23 counts of aggravated assault with a vehicle.

Mr Acevedo said it was an “intentional act,’’ and that the suspect has been booked and formal charges will be filed this afternoon.

Tragedy … Paramedics transport a person who was struck by a car on Red River Street in downtown Austin, Texas, at SXSW.Source: AP

Two people were in critical condition on Thursday morning with life-threatening head injuries and three patients remain in serious condition, said Dr Christopher Ziebell, the emergency department director at the University Medical Centre-Brackenridge said. He also said the driver was treated for minor injuries.

“The most critical patients I have a great deal of concern for,’’ Dr Ziebell said. “We are going to do our best for them, but these are some of the worst injuries that we see and not everybody with these kinds of injuries is going to survive.’’

The annual music, film and interactive conference draws tens of thousands to Austin each year, and the toll could have been much higher. The street had been packed with revellers just minutes earlier, but officials had cleared the area to create a fire lane.

“We had a large crowd,’’ Mr Acevedo said. “I just thank God that a lot of the folks had already been pushed on the sidewalk or this could have been a lot worse.’’

Austin police shut off traffic to about 2.5 square kilometres of downtown for five days during the festival, turning normally busy roads into a large pedestrian mall to help festivalgoers reach dozens of music venues.

Police said the incident started when an officer on a drink-driving patrol tried to stop the silver Toyota sedan at a gas station a few blocks away. The car took off, weaving between parked cars then driving at high speed the wrong way down a one-way street.

The driver rammed through police barriers – three wooden pieces held up by metal poles – set up on Red River Street on the northeast edge of the entertainment district near The Mohawk nightclub, where multiple acts were to perform on Wednesday night. The bands X and TEEN had just wrapped up, and rapper Tyler the Creator was scheduled to perform at 1am.

An injured man is transported to an ambulance after being struck by a vehicle on Red River Street in downtown Austin, Texas.Source: AP

An officer had to jump out of the way of the driver, Mr Acevedo said at Thursday’s news conference.

“We will review our procedures always, we always look at that. But understand something, when somebody acts intentionally, it’s very difficult to stop. You have a car here. You have a police officer that was forced to jump out of the way,’’ he said.

Scott Jakota, a musician from Indiana in town to play SXSW, told the Austin American-Statesman he was one of the first people hit outside The Mohawk. He said the driver “gunned’’ the car.

“I was thrown up in the sky,’’ Jakota said.

Overlooking the street, 28-year-old Ally Hulton from Los Angeles, was on a balcony of her friend’s apartment when she saw the car driving “at full speed’’ before hitting someone.

“About 10 bodies went flying,’’ Ms Hulton told the newspaper.

The festival will continue because of the thousands of visitors in town, SXSW managing director Roland Swenson said on Thursday morning. A spokeswoman for the festival said there would be schedule and venue changes.

“It would cause more problems for people to show up and be turned away than to carry on,’’ he said.

A crime scene unit was still investigating the crash, and Mr Acevedo said there were no plans to change safety protocols at the festival due to the accident.

“We do these events very well, but you cannot stop a person who rather than face drink driving charges decides to speed at a high rate of speed, go around a uniformed officer forcing him to run out of the way, then at a high rate of speed show total disregard for the sanctity of human life,’’ Mr Acevedo said.

Mr Acevedo asked witnesses and those who may have taken video to contact police rather than post it on the internet.

An estimated 32,000 people swarm through Austin for SXSW which runs from March 7 to March 16.